Electric oscillator.



D. G. McCA A.

ELECTRIC OSCILLATOR.

APPLICATION FILED 02130. I915.

1,246,626 Patented N0v. 13, 1917.

@L E? 7L lation to the c:

UNITED STATES Parana ()FFICE.

DAVH G. MOCAA, OF LA'NCSTER, PENNSYLVANIA, ASSIGNOR T0 RADIO 00M- PANY,0F LANCASTER, PENNSYLVANIA. A CORPORATION OF PENNYLVANIA.

Specification of Letters Patent.

ELECTRIC OSCILLATOR.

Patented Nov. 13, 1917.

This application filed October 30,

1916. Serial No. 128,448.

Lancaster, Lancaster county. State of Penn sylvania, have invented anElectric Oscillator, of which the following is a specification.

My invention relates particularly to apparatus for the production ofoscillatory currents of high frequency and the emisslon ofelectromagnetic waves.

As is known by those skilled in the art, a system of elevated conductorsplaced either above the earth or above a second system oi eonductorsclose to but insulated from the earth possesses a definite capacity rethor to said system and is capable of receiving electrical energy and ofstoring it. similarly to a condenser. If

' some means is provided of such a nature as to permit the storedenergy, upon reaching a certain maximum, to discharge into the earth orinto a system near the earth, a circuit including the first system willhave produced in it high frequency oscillations and a portion of thestored energy will be radiated as earthed clectron'lagnetic waves.

lleretofo're the mcans usnally employed for'discharging'the elevatedconductor was a spark gap, which during the discharge be came a part ofthe oscillator system in which an oscillatory current must nccessarilyflow. The spark gap, being of high resistance, caused a serious loss ofenergy and a material decrease in the number of oscillationsconsequent-upon each discharge, with a resulting increase in thedecrement of the oscillatioi'ls and the production of a wave of poortuning qualities. Moreover, I have found that in radio telephony, aspark gap in circuit with the microphone seriously interferes with thesatisfactory functioning thereof.

One objcct of the present invention therefore is to provide a device.for increasing the encrgystorago function of the elevated conductors inan oscillator system. together with means whereby the oscillationsproduced in said conductors are transferred to ting electromagneticwaves having good tuning qualities.

These ObjECtS and other, advantageous cnds l secure as hereinaftersctforth, reference being had to the accompanying drawings, in which, ligure 1 is a diagrammatic View illustratmg a system for producingelectro-magnetic waves in which the parts are arranged and connected inaccordance with my invention; and

Fig. 2 is a diagram illustrating a slightly modified form of theinvention.

In the above drawings, 1 represents a source of current, 2 a device formaking and breaking the flow of current in the circuit including saidsource and 3 the primary winding of an induction coil. This latter isprovided with a secondary winding 4 connected in a circuit. including acondenser 5 and a quenched spark gap 6. It is ob vious, however, that,without departing from my invention, any other suitable current sourceand controlling means may be provided for setting up. limiting andcutting ofi' current flow through said spark gap.

()ne terminal of the spark gap is conncclcd to a plain open circuitradiating or main antenna 77,'While its second terminal is connectedthrough a. coil 8 to the earth in such manner that the number of itsturns in circuit may be varied at will. This antenna will store energyaccording to the capacity rclalion between it and the earth and suchrelation will vary according to the type of said antcnna, being smallestin a straight vertical .orm and largest-wlien the antenna belongs to theinvcrtcd or umbrella type. 'It is noted that this capacity relation isncvcr vcry large and that the amount of encrgy stored before andradiated during discharge is limited.

By long contimicd experiments I have found that the capacity relationand energy storage function of the system or circuit comprised by theparts --68, can be greatly increased by arranging an auxiliary groundedconductor or series of conductors parallel to and interm eshing with themain conductors 7. With this idea in view I mount adjacent the latter asecond series of elevated conductors 9 connected to the earth 85 and thewaves emitted are sharp and of through a variable inductance and a coil11 adjustable as to the number of its turns in.- circuit, said coilbeing, mounted to serve as the secondary of an oscillation transformerwhose primary winding consists of the coil 8.

With such an arrangement of parts the circuit 91011 performs at leasttwo dosirable functions, of which the first is to increase the energystorage capacity of the circuit 76"8 during the charging of thela'tter;and the second is to receive the oscillations developed in thecircuit 7-6-8 and 9101186'7' and radiate the energy thus received duringthe discharge of said circuit. Another function is to form anoscillatory circuit consisting of the parts 91011 -8-6-7 which furtherincreases the energy storage ability of the system, there being thustwlo capacities, t. 6., that existing between the antenna 77 and theearth augmented by the earthed conductors 99, and that existing betweenthe antennav wires 7-7 and 9-9 independent of the earth connections.When the oscillations are set up in the circuit 768 by a dischargeacross the spark ap 6, which occurs upon the closure of the ey 2, theprimary winding 8 induces currents in the secondary winding 11, whichcurrents are supplied to the auxiliary conductors 9, causing the circuitin which they are included to act as a radiating antenna in which nospark gap is present. The oscillations produced in this antenna aresustained and of low decrement good tuning qualities.

It is particularly to be noted that owing to the presence of the systemor circuit 9-1011, there is no effectual radiation from the circuit768;-the waves produced by the apparatus being emitted solely by thefirst named .circuit when the adjustments of the coils 10-811 are suchas to cause a maximum transfer of energy from the circuit 7.6-8 to thecircuit 9-1011.

If the current readings in-the two circuits be taken, as by hot wiremeters, when the above adjustments are made, 'I have foundthat a maximumcurrent in the circuit 910-11 is accompanied by a minimum current in thecircuit 7-68, and vice" 10, and varying the number-of turns in the twocoils 8 and 11, in which case the number of turns in the coil 8 must begreater cuit 910-11867, and the electrical 7 equivalent of the systemshown in Fig. 1, is found in Fig. 2 where said two coils 8 and 11 may bereplaced by a single adjustable coil 12 connected between theearth andthe point of junction of one end of the coil 16 and one terminal of thespark gap, in which case said single coil likewise serves as anoscillation transformer.

There are therefore two oscillatory systelns supplying the radiatingstructure 9-1011, for in Fig. 1, the circuit 768 supplies this structureby means of the oscillation transformer 811 and the circuit 9-l011867supplies the structure 9-1011 by means of the coil 10,

which being common to both circuits operates as an auto transformer. InFig. 2 the same relations hold for both of the coils 10 and 12 act asauto transformers.

It .,will be seen (Fig. 2 that the circuits 7(512 and 9-106 are vecoupled to the circuit 910'12, f or aside from theelectro'magneticcoupling present in the oscillation transformers 10 and12, there is a capacity coupling between the wires comprising theantennae 7 and 9. This close coupling causes the system to be practicallthe quenched gap is used. With an ordinary gap in air, each primarysystemscts up oscillations of two different frequencies so that thereare four coupling waves and these are-of such a character as to beopposite to each other. Further, with an ordinary gap in air, inwhichthe osclllations are not quenched, the branch 7 carries current in onedirection and the branch 9 also carries current but in the oppositedirection as in a loop antenna, thus causing the pheclos'ely inoperativewhen any other than nomena found in such an antenna, 2'; 0., the

non-radiation of the fundamental oscillation.

As a result of extensive experiments I have found that a form or type ofimpulse excitation existswhen a quenched 'ga is. employed in anoscillatory s stem whic is designed in such relation to t 1e currentsupply. ,system. that a rapid succession of discharges occurs during theflow of each alternating current wave. The quenching of the primaryoscillations under these conditions, 11. 0., high group frequencies, isno setting up a (#enched oscillatory current flow in one saidconductors; an auto transformer in circuit with the other conductor; andan oscillation transformer inductively connecting said two conductors.

8;"A system consisting of main and auxilia i'y sets of conductors; meansfor setting up quenched electric oscillations in that part of the systemincluding one of said sets of conductors; a coil connected between saidset of conductors and the ground; a second coil in inductive relationwith the first coil and connected between the ground and the second setof conductors; with a variable inductance also including in circuit withsaid second set of conductors.

9. An oscillatory system consisting of a plurality of open oscillatorycircuits; a. radiating circuit coupled to said oscillatory circuits;means for transferring energy from said oscillatory circuits to theradiating circuit; and means for preventing said radiating circuit frominducing current in said open circuits.

10. An oscillatory system consisting of a plurality of open oscillatorycircuits; a radiating circuit coupled to said oscillatory circuits;means for transferring energy from said oscillatory circuits to theradiating circuit; and means for preventing effectual radiationfrom theopen circuits.

11. An oscillatory system consisting of elevated conductors forming aplurality of primary circuits and hav ng parts associated to providearadiating circuit coupled to said primary circuits; means fortransferring energy from said primary circuits to the radiating circuit;and means for preventing said radiatin circuit from inducing current insaid primary circuits. 12. An oscillatory system consisting of elevatedconductors forming a pluralityof primary circuits and having partsassociated to constitute a radiating circuit coupled to said primarycircuits; means for transferring energy from said primary circuits tothe radiating circuit; and means for pre venting effectual radiationfrom parts of said system other than the radiating circuit. 13. Atransmitting system consisting of a plurality of primary circuits havingportions associated to. constitute a radiating cir cuit, said primarycircuits bein out of resonance with said radiating'circuit and thelatter being coupled to the primary circuits under conditions of maximumradiation.

14. A transmitting system consisting of a plurality of primary circuits;a radiating circuit coupled to said primary circuits; with meansincluding a quenched gap for causing in said primary circuits anoscillatory current flow quenched by means other than the reaction ofthe radiating circuit. DAVID G. MoCAA.

